Connection and conflict: influence of the hidden curriculum on veterinary residents' professional identities within the specialty of laboratory animal medicine.

OBJECTIVE: To explore the role of the hidden curriculum in residents' development of professional identity during postgraduate training in laboratory animal medicine. SAMPLE: 24 residents enrolled in 1 of 7 laboratory animal medicine training programs in the eastern US. PROCEDURE: 24 qualitative, semistructured interviews were conducted and recorded. Deidentified transcriptions were analyzed by each author using open and axial coding. Constant comparative methodology was used to develop themes and subthemes. Member checks were performed to verify trustability of the conclusions drawn. RESULTS: 3 themes and their related subthemes emerged from the qualitative analysis: 1) building relationships through competent communication (building rapport, practicing clinical empathy, overcoming language barriers, communicating in the "authorized" way, and navigating email limitations), 2) tension within the process of identity formation (acting as the middleman among stakeholders, overcoming the stigma of the policing role, experiencing a lack of power to impact change, and managing a culture of conditional value of veterinary knowledge), and 3) outlets for tension in identity formation (reliance on residency mates, limitations of venting). EDUCATIONAL RELEVANCE: Our findings suggest that residents are navigating professional identity formation under challenging circumstances that include conflicting stakeholder needs, conditional value of veterinary knowledge, and lack of power to influence change. Residents have limited outlets for relieving the discord between their ideal professional role and their lived experiences. These results provide an important background for refining curricula and creating effective support systems for residents.

Evaluation of alfaxalone total intravenous anesthesia in rabbits (Oryctolagus cuniculus) premedicated with dexmedetomidine or dexmedetomidine and buprenorphine.

OBJECTIVE: To evaluate alfaxalone for total intravenous anesthesia (TIVA) in rabbits premedicated with dexmedetomidine or dexmedetomidine and buprenorphine. STUDY DESIGN: Crossover study (part 1) with observational study (part 2). ANIMALS: A total of eight New Zealand White rabbits (Oryctolagus cuniculus), four female and four male, aged 12-16 weeks and weighing 2.8-3.5 kg in part 1. Separately, four additional rabbits in part 2. METHODS: Crossover study design with eight rabbits per treatment. Rabbits were administered treatment D, dexmedetomidine (0.2 mg kg-1), or treatment DB, dexmedetomidine (0.1 mg kg-1) and buprenorphine (0.05 mg kg-1) intramuscularly. Anesthesia was induced with alfaxalone intravenously until a supraglottic airway device was placed to deliver 100% oxygen. Anesthesia was maintained with alfaxalone (TIVA). Infusion rates were adjusted to achieve an absent pedal withdrawal reflex. Heart rate, respiratory rate, noninvasive blood pressure, end-tidal carbon dioxide partial pressure and peripheral hemoglobin oxygen saturation (SpO2) were recorded every 5 minutes. Subsequently, four rabbits underwent ovariohysterectomy using treatment DB and alfaxalone TIVA. RESULTS: The mean ± standard deviation alfaxalone infusion rate was 9.6 ± 2.6 and 4.5 ± 1.3 mg kg-1 hour-1 for treatments D and DB, respectively. In both treatments, blood pressure remained within acceptable range and SpO2 was > 95%. Postinduction apnea and respiratory depression were observed in both treatments and managed with manual positive pressure ventilation. Four separate rabbits underwent successful ovariohysterectomy with treatment DB and alfaxalone TIVA. One rabbit required supplementation with inhalant anesthesia; three rabbits were successfully maintained using alfaxalone TIVA alone. CONCLUSIONS AND CLINICAL RELEVANCE: Premedication with dexmedetomidine-buprenorphine combined with alfaxalone TIVA may be a viable alternative for performing abdominal surgery in the rabbit. The use of supplemental oxygen and ability to provide respiratory support are advised.

Surgical treatment of spontaneous endometriosis in rhesus macaques (Macaca mulatta): 11 cases (2007-2011).

OBJECTIVE To determine long-term outcome for rhesus macaques (Macaca mulatta) with endometriosis that underwent surgical treatment and identify factors potentially associated with long-term outcome. DESIGN Retrospective case series. ANIMALS 11 female rhesus macaques. PROCEDURES Medical records of female rhesus macaques in which endometriosis was diagnosed between 2007 and 2011 and that underwent abdominal exploratory surgery were reviewed. RESULTS In 5 macaques, the only clinical abnormality was a caudal abdominal mass identified during a routine physical examination, and in 6 macaques, overt clinical signs of endometriosis, including anorexia, dysmenorrhea, and lethargy during menses, were reported. Five macaques had histologically confirmed complete ovarian removal, and another 5 had incomplete ovarian removal (ovarian tissue was not examined histologically in 1 macaque). Nine animals survived at least 12 months after surgery, and 6 survived at least 60 months after surgery. Macaques that did not have overt clinical signs were significantly more likely to survive at least 60 months after surgery. However, extent of ovarian removal was not significantly associated with survival 12 or 60 months after surgery. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that, in select situations, surgery (ovariectomy or ovariohysterectomy) may be curative in macaques with endometriosis and may result in long-term survival. Further, findings suggested that monitoring until clinical signs appear before performing surgery is not warranted in adult female macaques suspected to have endometriosis that only have a caudal abdominal mass and no other overt clinical signs.

Intramuscular Administration of Alfaxalone Alone and in Combination for Sedation and Anesthesia of Rabbits (Oryctolagus cuniculus).

This study compared alfaxalone, alone and in combination with other medications, for sedative and anesthetic properties after intramuscular administration in New Zealand white rabbits. In the main portion of the study, 6 female rabbits were assigned to 5 treatment regimens in a blinded crossover design. Alfaxalone (6 mg/kg IM) was administered alone and in combination with each of the following: 0.3 mg/kg butorphanol; 1 mg/kg midazolam; 0.2 mg/kg dexmedetomidine; and both 0.3 mg/kg butorphanol and 0.2 mg/kg dexmedetomidine. An additional 6 rabbits received 0.2 mg/kg dexmedetomidine for comparison. The median time to onset of recumbency ranged from 2.0 to 5.5 min, with times significantly shorter for animals that received alfaxalone with either midazolam or dexmedetomidine than for those given dexmedetomidine only. Duration of sedation (mean ± 1 SD) was: alfaxalone only, 40 ± 7.3 min; alfaxalone with butorphanol, 47.8 ± 9.9 min; alfaxalone with midazolam, 65.2 ± 6.5 min; alfaxalone with dexmedetomidine, 157.5 ± 22.4 min; alfaxalone with butorphanol and dexmedetomidine, 157.7 ± 22.3 min, and dexmedetomidine only, 93.7 ± 11.9 min. Response to noxious stimuli was absent in 2 of the rabbits given dexmedetomidine only, 4 of those given alfaxalone with dexmedetomidine, and all 6 of the animals dosed with alfaxalone, butorphanol, and dexmedetomidine; this last group displayed the longest absence of a toe-pinch response (57 ± 3 min).

Effects of subcutaneous alfaxalone alone and in combination with dexmedetomidine and buprenorphine in guinea pigs (Cavia porcellus).

OBJECTIVE: To characterize alfaxalone administered subcutaneously (SC) in guinea pigs, both alone and in combination with dexmedetomidine and buprenorphine. STUDY DESIGN: Prospective, blinded, crossover study. ANIMALS: A total of 15 healthy female guinea pigs weighing 400-600 g. METHODS: Alfaxalone (10, 20 and 40 mg kg-1) was administered SC to three guinea pigs as a pilot dose-finding study. Alfaxalone (20 mg kg-1; A20) was selected for comparison against combination protocols of alfaxalone (15 and 20 mg kg-1) with dexmedetomidine (0.25 mg kg-1) and buprenorphine (0.05 mg kg-1; A15DB, A20DB). Each protocol was randomly administered to 12 guinea pigs separated by ≥7 days. Time and quality of induction and recovery, heart rate, respiratory rate, peripheral hemoglobin oxygen saturation, rectal temperature, pedal withdrawal reflex and adverse effects were recorded. RESULTS: The median time to induction for A20, A15DB and A20DB was 6.8-8.0 minutes with no significant difference between treatments. Mean duration of recumbency for A20 was 73.6 ± 19.6 minutes. Recumbency duration for A15DB and A20DB extended to 90 minutes, at which time dexmedetomidine was antagonized using atipamezole (0.025 mg kg-1 SC). Physiological variables were within normal limits with the exception of one animal that died 45 minutes following treatment with A20DB. Pedal withdrawal reflex remained intact with all treatments. Minor side effects such as twitching or bruxism occurred sporadically with treatment A20 but not with A15DB and A20DB. CONCLUSIONS AND CLINICAL RELEVANCE: SC alfaxalone produced uncomplicated sedation that may be recommended for nonpainful procedures that do not require complete immobility. The addition of dexmedetomidine and buprenorphine increased the duration of sedation and immobility, but did not result in general anesthesia. This combination sedation protocol may be useful for nonpainful procedures requiring extended immobility.

Surgical Correction of Rectal Prolapse in Laboratory Mice (Mus musculus).

Rectal prolapse is a common clinical problem in laboratory mice. This condition may occur spontaneously, develop after genetic manipulations, result from infections with pathogens such as Citrobacter species, or arise secondary to experimental design such as colitis models. The current standard of care at our institution is limited to monitoring mice until tissue becomes ulcerated or necrotic; this strategy often leads to premature euthanasia of valuable animals prior to the study endpoint. Surgical correction of rectal prolapse is performed routinely and with minimal complications in larger species by using manual reduction with placement of a pursestring suture. In this report, we investigated whether the use of a pursestring suture was an effective treatment for mice with rectal prolapse. The procedure includes anesthetizing mice with isoflurane, manually reducing prolapsed tissue, and placing a pursestring suture of 4-0 polydioxanone. We have performed this procedure successfully in 12 mice. Complications included self-trauma, fecal impaction due to lack of defecation, and mutilation of the surgical site by cage mates. Singly housing mice for 7 d postoperatively, applying multimodal analgesia, and releasing the pursestring when indicated eliminated these complications. The surgical repair of rectal prolapses in mice is a minimally invasive procedure that resolves the clinical symptoms of affected animals and reduces the number of mice that are euthanized prematurely prior to the study endpoint.

Use of Femoral Head and Neck Ostectomy and Physical Therapy to Manage Osteoarthritis in a Rhesus Macaque (Macaca mulatta).

Osteoarthritis is associated with pain and immobility in both humans and animals. However, available resources for osteoarthritis management in captive NHP are limited. This case report describes a novel management strategy for a 10-y-old male macaque with unilateral hindlimb lameness, prominent muscle wasting, and severely limited range of motion. Radiographs of the affected limb showed lytic lesions of the femoral head. To relieve pain and improve mobility, femoral head and neck ostectomy (FHO) was performed, and multiple pharmacotherapies were initiated. The macaque also received a unique method of physical therapy that required no sedation, acted as enrichment, and was implemented by using a conventional caging system. The response to therapy was monitored by measuring thigh circumference in the operated and nonoperated limbs, which demonstrated improvement in both legs. The unique physical therapy in conjunction with surgery and pharmacotherapy benefited the macaque with osteoarthritis by reducing discomfort and improving mobility.

Enucleation for treating rodent ocular disease.

Our standard of care for rodent corneal lesions previously included treatment of the primary lesion, application of topical NSAIDs, and systemic NSAIDs in severe cases. When intensive medical management was unsuccessful, animals were euthanized, leading to premature loss of valuable genetically modified animals and those on long-term studies. We investigated enucleation surgery as a treatment for 15 cases of rodent corneal disease that did not respond to medical management. Enucleation was performed under isoflurane anesthesia and involved removal of the globe, extensive hemostasis, and packing the orbital space with absorbable gelatin sponge. The lid margins were closed by tarsorrhaphy and tissue glue. Analgesia was provided by using buprenorphine preoperatively and carprofen chew tabs postoperatively. To date, we have a 100% success rate with this procedure (n = 20; 15 clinically affected rodents [2 rats, 13 mice], 5 healthy controls), which included a 60-d follow-up period. The single complication involved dehiscence of the tarsorrhaphy site and was repaired by trimming the lid margins to provide fresh tissue for closure. Histologic examination at both 1 and 3 mo after surgery revealed no evidence of infection of the enucleation site. Enucleation in rodents is a straightforward procedure that represents a refinement to our current standard of care for rodents, does not cause significant inflammation of remaining periocular structures, and has reduced the number of animals euthanized prior to study endpoint because of severe ocular lesions.

Prothrombotic effects of thrombolytic therapy in a rat (Rattus norvegicus) model of venous thrombolysis.

The use of thrombolytic agents has greatly improved patient outcomes, but the prothrombotic response to these drugs in vivo is unknown. Approximately 24 h after we induced thrombosis in male Sprague-Dawley rats, we placed an infusion line in the inferior vena cava and administered either saline or a thrombolytic agent (tissue plasminogen activator [tPA] or plasmin) for 30 min. Blood was drawn immediately after infusion; rats were euthanized 24 h after infusion for collection of blood and tissue (inferior vena cava and thrombus). Thrombus size was decreased in the tPA-treated rats but not in those that received saline or plasmin; this change correlated with the significant rise in D-dimer levels noted immediately after infusion in the tPA-treated rats. Plasma soluble P-selectin, a prothrombotic marker, was elevated at 24 h in the plasmin group compared with the other treatment groups. There were no significant differences in plasma C3a, C5a, or C5b9 levels or in thrombus C3 levels between groups. According to ultrastructural analysis, thrombus structure and vein wall effects did not differ between groups. Local tPA did not induce a prothrombotic state during acute DVT or after thrombolytic therapy in a rodent model of venous thrombolysis. Conversely, levels of the prothrombotic marker plasma soluble P-selectin increased when plasmin was administered.

Effects of short-term fasting in male Sprague-Dawley rats.

Fasting is a common procedure for animals in experiments. Although fasting may be necessary for scientific reasons, it should be minimized. In the current study, jugular-catheterized male Sprague-Dawley rats in metabolism cages were fasted for 0 to 24 h before measurement of various physiologic markers (serum chemistry, CBC analysis, serum corticosterone). When controlled for cohort, rats fasted for 6 and 16 h had significantly lower serum glucose than did nonfasted rats. Other values did not differ from controls. Only rats fasted for 24 h had elevated serum corticosterone levels. Therefore, fasting for as long as 16 h has fewer effects on rats that does fasting for 24 h. Fasting for 24 h or more therefore should receive appropriate consideration by both scientists and the IACUC in the experimental design and the animal-use protocol.